Past and present developments in polymer bead foams and bead foaming technology

Polymer bead foaming technology has expanded the market for plastic foams by broadening their applications because of the breakthrough in the production of low-density foamed components with complex geometrical structure. This review presents the recent advances in the processing, sintering behaviour and properties of bead foam products, which possess unique advantages such as excellent impact resistance, energy absorption, insulation, heat resistance, and flotation. The key features such as the mechanical properties of the commercially available bead foams, namely expanded polystyrene (EPS) and expanded polypropylene (EPP), are presented. Furthermore, recent developments of new types of bead foams based on biopolymer such as expanded polylactide acid (EPLA) and engineering thermoplastics such as expanded thermoplastic polyurethane (ETPU) and expanded poly(butylene terephthalate) (EPBT) are discussed. (C) 2014 Elsevier Ltd. All rights reserved.